Ulrich Windl wrote:
>>> Christian Kratzer <ck-lists(a)cksoft.de> schrieb am
10.08.2013 um 19:43 in
Nachricht <alpine.BSF.2.00.1308101942120.18017(a)pohjola.cksoft.de>:
> On Sat, 10 Aug 2013, Michael Ströder wrote:
>> Are contextCSN values on all replicas really in sync if changes were
> correctly
>> replicated?
>>
>> I've implemented a monitoring check used with normal MMR setup (OpenLDAP
>> 2.4.35, own build on Debian Squeeze) which also checks the contextCSN
values
>> on all replicas compared by server-id.
>>
>> Sometimes we observe, even in isolated tests, that contextCSN values for a
>> certain server-id differ for quite a while (up to hours) even though the
>> changes coming from that server were definitely replicated to all other
>> replicas. After a while the contextCSN values get suddenly updated.
>> Unfortunately this does not always happen.
>>
>> Any hint is highly appreciated.
>
> I have always suspected that this is due to the specific setting of:
>
> syncprov-checkpoint <ops> <minutes>
> After a write operation has succeeded, write the contextCSN
> to the underlying database if <ops> write
> operations or more than <minutes> time have passed since the
> last checkpoint. Checkpointing is disabled
> by default.
>
> Not sure though.
do you "query" by slapcat or by an LDAP search? For the former it's
documented
that contextCSN is updated lazily. For the latter I'm not sure.
Using slapcat in a monitoring check invoked every minute would be pretty dumb.
So of course I'm retrieving the contextCSN values from replicated DBs via LDAP.
Ciao, Michael.